Surface marking signal



Feb. 16, R Q LlNCK SURFACE MARKING SIGNAL Filed May 26, 1952 Patented Feb. 16, 1954 UNITED STAT lil-Sv PAT F F ICE 2,669,211y SURFAGEQMARKING. SIGNAL- tobet fiinck, San J'an, P. R.

vitl-pnaaien Mayas), 1952, serial Netizeoaoa (C1. 11e-2e) 10 Claims. l

This invention .relatesto a drop. type :of signal which when `:dropped from ,an .aircraft bursts 'on impact .with .a surface and. provides for marking of acontinuous, homogeneous fvisiblez'spot on the surface, in a time interval approaching that 'minimum ``time requir'edfor free/fall from the same altitinie.l

`During' World War .IIfaasign'al bomb of molded composition; approximately .ten inches in length with 'alstandard'our Vane tail such as disclosed in the U. S. Patent 2,338,719; .issued-"Januaryll, 1944,1iwasused primarily from airplanes .asa drift n'clicator` The bomb was fofwconventional tear.

droprsha'peand its characteristics, Aas explained II-,: :it fha-sheen found. that the "use .o'fzzsiich .prior drop. signals as disclosed in lthe referred. to 'Ui Ss.

Patent 2,338,719Jz `are .not satisfactory as v.it-.;has been found.V that failures .to. :burst :upon` impact runafrom` 30 Vto fiovifvvlsiexrv :dropped lffroni slow. moving and. low .ilying airships ywhiczli have vmore recently been .adopted asone fof .the principal.

detecting. units in the fsonar system.;.

The tsurface marking signal .accordingfto lmy invention Lis :particilarlyfusefulinf-drops from slow. moving aircraft-such as made 'at .zero speed aswhen they are -turningmto the-'wind andfr'onix altitudesof 50 to 'l5 feet and even las. :low as 15:`

feet-above the Surface von which the Lsurface markingis to be madeA The reasons 'for the failures of the 'prior art Itypefof drop signal are that operations-are now being conducted'at heights of from 50.to 75 feet yand even less. Thespeeds of. the. aircraft'from. which the ksignals arer dropped.r zare Talmost -z'ero as would `'occur when aiishlps 'are turning into fthe-wind v'and 'wh-ich require #dropping :of the :signal: at .such yan Eine stent: Thexsurfacefmarking signal of the prior art which "uss fafshell .or jcasinghavingra round conventional 'tear drop formation produces :too muclifistrength to assure iractur'ability under opJ existing-conditions of slow speed vand low altitude as now exist.- In `the lpr-ior vart 'the drop signals i were provided `with dus Vto assist them.. irl-reachingel 'desi-redspot on the surface belowyhowever,

such tail nnsiare not `.necessary 'inudropbombs dropped .froid-.relatively low.lalti'tudes.-y lvsLit''is dlifiraliletriest` trici-'drop 'signalxtake up thevleastf:

face marking signal which when'dropped fromy slow movingaircraft :at `relatively low altitudes willfrall ina time intervalapproaching that minimum time Arequired 'forfree fall from the same altitude and will burst `on striking the surfacev below. and will leave amark of a continuous,

homogeneous `and visible spot on the surface and yet will withstand lrbreakage in kordinary handling and transporting..

A further object of my invention is to provide a surface marking :signal which is of relatively small size such as theorde'rfof seven inches long and three and `a quarter inches of maximum widthfwhicli yis 'elongated in shape and has a plurality of fflat surfaces which enhance its bursting ability'whn dropped'from low altitudes.

A :further object of my invention is to provide an elongated ysurface marking signal including a casing having par'allel lat ends and a plurality of angularly disposed .flat sides and containing marking powder to such a degree that a void space is-provided between 'the powder andthe casing so that fit will not be deformed or fractured diie to-c'zliari'ges vpressure such as will ob-' tain in an aircraft 'as the result of sudden changesin altitude.

A sti-lllfiirther object of my invention is to pro.

vide a :relatively srn'all surface marking signal whichl may Abe `readily Afhandled without breakage but will 'burst lwhen dropped from low altitudes at slowspds and` isinold'ed of inorganic plastic and which has an elongated casing with one end portionhaving a shape of .a frustum of a regular pyramid .having vitssides diverg'ing outwardly fromeach other as theyextend from a -iiat end thereon towardthe other fend of the `vcasing and the front remainngpor-tion of l'the casing yhas a aecaaii 3 shape of a frustum of a regular pyramid having its sides converging toward an adjacent end which is apertured to receive the marking powder therethrough and which aperture is covered with a porous material permitting passage of air therethrough but impervious to the passage of the marking powder contained within the signal. Still further objects and the entire scope of applicability of the presen-t invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific example is given by way of illustration only, and while indicating the preferred embodiment of the invention, is not given by way of limitation, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

One form of this invention which is now successfully in use, is shown by way of example, in the accompanying drawing, in which,

Figure l is a perspective View of the marking signal shown resting in a vertical position on the fiat tail end thereof;

Figure 2 is a vertical cross section of the marking signal; and

Figure 3 is a cross section as viewed along section line 3-3 in Figure 2,

Throughout the various figures of the drawing and the specification, like reference numerals refer to similar parts.

The drop signal or bomb is generally indicated at Ill and is comprised of a casing having a rear end portion I I and a front portion I2 integrally and abuttingly connected thereto which is provided with a flat front end I4. Flat front end I4 is apertured as indicated at I3 so as to provide an access for lling the interior of the casing with a marking powder I 1.

The marking powder Il may be any suitable color and include bronze powder, fiuoresceins and chrome yellow so treated as to remain suspended on the surface of the water and is of such a charac-ter that it will spread spontaneously on the surface of the water to form a coherent film. Marking signal I Il is filled with the powder Il to a level such as indicated at l Si just below the filling aperture I3 thus providing a void space between the powder surface Iii and the casing permitting expansion and contraction of the powder.

The front end I4 of the front end I2 of the casing is provided with a powder filling and access aperture I3 that has a closure I5 which may be fabric porous material such as industrial tape. Tape I5 is stretched over the end I4 and secured to ythe front portion I2 by adhesive disposed intermediate the surface of the casing and the inner side of the tape. The closure I4 for aperture I3 is further held secure on the side walls of the front end I 2 by a sealing compound I6 which is applied so as to overlap the edges of the fabric I4.

In Figure 2 the elongated marking signal or casing It is shown with its longitudinal axis Y-Y extending therethrough and the shell portions II and I2 forming the rear and front portions respectively are symmetrically disposed about the longitudinal axis Y-JI. The rear portion I I extends for about 75% of the whole length of the casing as measured along the major axis Y--Y while the front portion I2 extends for the balance of the length of the casing. The rear portion II has a fiat tail end I9 andi-s of a shape of a frustum of a regular pyramid. The front 4 portion I2 abuts the front end of the rear portion I I in the plane X-X which is transverse to the major axis Y--Y. The front portion I2 extends oppositely from the rear portion II along the major axis Y-Y and has a shape of a frustum of a regular pyramid terminating in the flat front end I4 which i5 transverse to the major axis Y-Y. The amount of the area of the tail end I1 which is also transverse to the axis Y-Y is less than the amount of the area of the front end I4 and the front end I4 is of a lesser area than the area formed by a plane containing the minor axis X--X and lying as a juncture plane betweenthe abutting rear portion II and the front portion I2.

In the particular form here shown each portion I I and I2 is formed of four flat sides wherein the sides of the rear portion II diverge outwardly from the flat tail end I'I while the sides of the front portion I2 converge towards the front end I4. The inner surfaces of the sides forming the rear portion II and the front portion I2 are flat and smooth and provide for a surface against which the powder Il will not pack or cake nor adhere but against which it flows freely. Thus,

when the bomb is dropped and it bursts all cf the powder is expelled from within and slides freely off of the sides and particles so that it is not carried below the surface of the water by the particles but is allowed to remain and float on the surface of the water.

It is possible that rear and front portions II and I2 may be made with more than four sides, however, the four sides here illustrated are preferred as they provide a shape for the casing which readily fractures on impact, particularly when dropped from relatively low altitudes at very low speeds of the airship or aircraft from which the signal is dropped.

The overall length of the actual example here shown is 71A; inches and the maximum width along the minor axis X-X is of the order of 31A; inches. The thickness of the cross section of the casing is of the order of 1/8 to of an inch. The

material of which the casing may be made is an inorganic plastic composition which may be rendered liquid with heating to produce a readily owable liquid mass. This composition contains a thermal plastic binder material and various' fillers and pigments. Such a composition may be heated to liquefy it and it may thereupon be poured or cast in molds.

either of such extreme high or low altitudes.

This marking signal may be given relatively high initial velocity as with a simple catapult or even by means of hand throwing but it will not fracture until it strikes a surface onto which it is.

projected to leave a visible signal or mark.

In the particular example here shown the loaded marker has a center of gravity approximately falling at C. G. which approximately lies in the plane of juncture X--X between the rear `portion Il and the front 'portion I2 and along When it is allowed to set, the composition solidifles to form a fran-A The menaante frontend l2 downward? if i-tlisdropped with-its tail? 'l1-end Il 9 :down` it fwi fone-naif fa f. turn the lpowder -Il readily lslides thereover and falls therefrom providing the maximum use of. the powder for niark'ing purposes.

It has lceenfjcfoundA that -theseemailcing signals are highly reliable for handlingfat both highffandi;

low-altitudes and at great speedsand yet-when dropped from. either high or lowal-titudes-ionto a surface, afford a highv fidelity of .breakage ,thus makingthem highly useful asia-.surface `marking signal.

, .I claim asmy invention:

l.' A surface marking signal' containing powder for marking purposes and adapted to burst upon impact comprising an elongated casing of frangible material with its major axis extending therethrough and comprising a rear portion and an abutting front portion, said rear portion extending for about 75% of the whole length of the casing as measured along said major axis while the front portion extends for the balance of the length of the casing, said rear portion having a shape of a frustum of a regular pyramid terminating in a fiat tail end disposed transverse to said major axis, the flat tail end having an area smaller than the area of a juncture plane extending transverse to the major axis and disposed between said abutting rear and front portions, said front portion abutting said rear portion at said juncture plane and extending oppositely from said rear portion along the major axis and having a shape of a frustum of a regular pyramid terminating in a flat front end having an area of an amount intermediate the amount of the area of said flat tail end on the rear portion and the amount of the area of said juncture plane between said rear and front portions, said flat front end having a filling access aperture extending therethrough for inserting of marking powder, and a closure for said aperture of material porous to the passage of air but impervious to the passage of powder, whereby said casing will not be deformed or fractured when handled and due to changes in pressure such as will obtain in an aircraft as a result of sudden changes of altitude.

2. A surface marking signal according to claim 1 wherein said casing is molded of inorganic plastic composition.

3. A surface marking signal according to claim l wherein said powder is of a character that will spread spontaneously on the surface of water to form a coherent lm.

4. A surface marking signal according to claim 1 wherein said closure for said aperture in the flat end of the front portion is a porous industrial tape which is secured to said front portion and over said aperture by adhesive, said fabric being porous to the passage of air but impervious to the passage of said marking powder.

5. A surface marking signal according to claim 1 wherein the rear and front portions having a shape of a regular pyramid each have four sides and the flat end tail of the rear portion, the juncture plane between the abutting portions and y Thus when ithisibomblisdropped fit will orient itselfso-'as fto fall-with tire the flat .fendiof lthe l:fron-irwrittenhating:"the #fili-S ing-ffaperture therein..fa-reactfsquare :coniiguratipn.v

.6: A surface-marking vfsigxml accordingito icl-aim:

1 wherein-said fcasi-ngis fmoldedn norganicpias.-

1 ticeicomposition; saidpowder .is of al character. that will sprea'dspontaneouslypnrthe fsurlfiacecf.. waterftofform la :coherent upony mursting pff said.'casing,,on.impactaidfclosure forsa'dfaperl ture inthe flat endof -`the fron-t portion is a/.porous =industrial tape-which secured. torsaidlfront. portion and onerksaid. aperture-.ibyadhesivaf said 1 fabric being porous totheipassage'pfiair :but

pervious to f the passage :.,of said `marking powder, and. said rearand front .portions :having -azshape foff'a l,regniar .pyramid each -Shave fourzfsides ,and the-'fiat .end `tail of: :the rear portion. the fjun'ei ture plane between the abuttingaport-ionsfand the end of y'the rfront portion `vlfiaving theeiilling aperture sthereiri :are fof :squarevv configuration.

7l; Asurfa'cemarkingfsignai containing powder for vmarking: :purposes and adapted. to burst 'upon impact fiincluding, vin'. :corribination, an 4.elongateii casing of frangible material with its major axis extending therethrough and comprising a rear portion and an abutting front portion, said rear portion extending for about 75% of the whole length of the casing as measured along said major axis while the front portion extends for the balance of the length of the casing, said rear portion having a shape of a frustum of a regular pyramid terminating in a at tail end disposed transverse to said major axis, the flat tail end having an area smaller than the area of a juncture extending transverse to the major axis and disposed between said abutting rear and front portions, said front portion abutting said rear portion at said juncture plane and extending oppositely from said rear portion along the major axis and having a shape of a frustum of a regular pyramid terminating in a flat front end having an area of an amount intermediate the amount of the area of said flat tail end on the rear portion and the amount of the area of said juncture plane between said rear and front por-y tions, said iiat front end having a lling access aperture extending therethrough for insertion of marking powder, said casing being filled with marking powder to an amount to provide a void space within the casing thereby permitting expansion and contraction of said powder and so that the center of gravity of said signal when in a position of rest on said flat tail end of the first portion lies substantially in the juncture plane between said abutting rst and second portions and on said longitudinal axis, and a closure for said aperture of material porous to the passage of air but impervious to the passage of powder, whereby said casing will not be deformed or fractured when handled and due to changes in pressure such as will obtain in an aircraft as a re sult of sudden changes of altitude.

8. A surface marking signal containing powder for marking purposes and adapted to burst upon impact including, in combination, an elongated casing molded of inorganic plastic composition adapted to burst on impact such as when dropped from an altitude as low as about 15 feet having a plurality of flat sides joining with a flat surface at each end, one of said ends having a filling access aperture` extending therethrough for insertion of marking powder, said casing being filled with marking powder to an amount to provide a void space within the casing thereby permitting expansion and contraction of said powder, the inside surface of each of said flat sides being at and smooth whereby the powder does not pack or adhere thereagainst but readily flows thereover, said end having the filling aperture being larger in area than said other opposite end, the center of gravity of said signal being nearer said apertured end and a closure for said aperture in the end of a material porous to the passage of airy but impervious to the passage of powder, whereby said casing will not be deformed or fractured when handled and due to changes in pressure such as will obtain in an aircraft as a result of sudden changes of altitude.

9. A surface marking signal according to claim 8 wherein the rear portion of said elongated casl approximately at the plane of juncture of said rear and front portions and on the longitudinal axis of said elongated casing.

10.V A surface marking signal according to claim 9 wherein said closure for the apertured end is a porous industrial tape which is secured to said front portion and over said aperture by adhesive, said fabric being porous to the passage of air but impervious to the passage of said marking powder.

ROBERT O'. LINCK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,124,768 Lowry Jan. 12, 1915 1,226,905 Neumann May 22, 1917 2,338,719 Holt Jan. 11, 1944 2,439,598 Dinsley Apr. 13, 1948 2,459,267 Dwyer Jan. 18, 1949 2,477,274 Trecek July 26, 1949 

